I guess it depends on what you call "the extra trouble." If the camera is on a tripod, has been carefully focused eg with live view, AND you care about the results, how can it NOT be worth it. I do not know about the Canon system, but in the world of Nikon, it's quite easy, a simple turn of the dial sets it. Attach the cable, push once, mirror up, wait however long you feel is necessary, push it again and the shutter is released, seems pretty simple.

I guess it depends on what you call "the extra trouble." If the camera is on a tripod, has been carefully focused eg with live view, AND you care about the results, how can it NOT be worth it. I do not know about the Canon system, but in the world of Nikon, it's quite easy, a simple turn of the dial sets it. Attach the cable, push once, mirror up, wait however long you feel is necessary, push it again and the shutter is released, seems pretty simple.

Even with a Canon system "the extra trouble" of going back to reshoot the scene because the image was blurry is likely to be greater than "the extra trouble" of using MLU and a cable or self-timer (on a tripod, of course).

Canons have two different self-timer settings, a long one and a short one. I use the long when I want to compose a picture and then jump into it myself (mostly travel shots with my wife). I believe that one is about a 10 second delay.

I use the short one, 2 seconds or so I think, for tripod shots in conjunction with mirror lockup. It's really the easiest thing you can do to improve sharpness. No need to carry a cable release either: press the shutter, mirror comes up, shutter opens 2 seconds later. Also works with live view.

The easiest thing to do is set one of the custom shooting modes to activate both mirror lockup and short timer. I'm pretty sure all mid range and high end Canon DSLRs can do that, and probably most others as well. On my camera, I often use C1 for HDR. The key settings are mirror lockup, manual exposure, short timer.

There seems to be some little bit of confusion about live view (LV) vs mirror lock up (MLU) on Canon SLR's. On many Canon SLR's is accessed via the menu system. Once it is engaged, the view finder is blocked by the mirror in the up position. With LV, the mirror is up but the image can be viewed on screen. Moreover, one can inspect the RGB histogram in real-time as you vary the composition or, for example, zoom your lens. Most importantly for landscape work on a tripod or other rigid support, you can examine the image at 5x or 10x zoom, with 10x corresponding to the pixel level. This feature makes focusing fool proof. If it looks like it is in focus on the screen at 10x, it is. You are not looking through the optical view finder and hoping that the camera focus system and focus on the sensor coincide. There are also options that further reduce vibration, but I forget what they are called. Maybe someone will comment.

All in all LV is a very important feature for landscape photographers. Oh! Did I mention that you invoke it by pushing a button on the back of the camera. The esteemed Michael R used to beg for an MLU button; this is much better.